Patent Application
20250102600
The present application claims priority under 35 U.S.C. § 119 to Japanese Patent Application No. 2023-158720, filed Sep. 22, 2023, the content of which is hereby expressly incorporated by reference, in its entirety, into the present application.
The present invention relates to a support device during subject setup in an imaging space in an imaging apparatus such as a magnetic resonance imaging (MRI) apparatus, and particularly, to a setup support technology including mounting of a receive coil.
In an examination using an MRI apparatus, a receive coil for receiving a nuclear magnetic resonance signal is mounted on an examination site of a subject, the examination site of the subject is disposed in an imaging space in which a static magnetic field is generated, and imaging is performed. In order to perform imaging to obtain a good image, it is important that the receive coil is appropriately mounted at an appropriate position of the subject and that the examination site is reliably positioned substantially at a center of the static magnetic field. In addition, the imaging space is formed in a relatively narrow bore, and the subject on which the receive coil is mounted is transported into the narrow bore in a state of lying on a bed. Therefore, it is important to secure a safe transportation operation. That is, it is necessary to proceed with the operation such that no accidents occur, such as the receive coil or a cable thereof mounted on the subject getting caught on other structures during the transport, or the subject hitting an entrance or an inner wall surface of the bore, which may cause falling from a predetermined position of the bed.
Various proposals have been made in order to appropriately perform the setup from the mounting of the receive coil to a magnetic field space. For example, JP2018-183525A discloses a technology of analyzing movements of a subject, equipment used for imaging (a receive coil or the like), an operator, and the like from an image acquired by a camera to monitor whether a series of operations (workflows) are appropriately proceeding, in which safety validity in at least one state is determined, and a warning is issued.
In addition, JP2013-248402A proposes acquiring 3D image data of a subject positioned on a patient table device, acquiring information on the subject, for example, information as to whether the subject or an accessory unit (a receive coil or the like) mounted on the subject protrudes from the patient table device, from a temporal change of the 3D image data, comparing the information with a safety value, and outputting a result.
Further, JP2022-508337A proposes a system that calculates a difference between an artificial image generated by using a generator neural network and optical imaging data and that determines an abnormal event that has occurred during setup in an AI-based manner to issue a warning. The abnormal event is considered to include inappropriate disposition or connection of the coil, occurrence of a cable loop or a body loop that may act as an occurrence source of an induced current, and the like. JP2022-124633A proposes a technology further specialized in detecting a loop during transport.
An especially important item in an example of the setup operation from the mounting of the receive coil to the transport to the magnetic field space is that the receive coil is mounted at an optimal position of the subject in order to obtain high image quality and that safety is secured in the transport in that state.
In the related art, a state of the subject during transport with the receive coil mounted thereon is monitored, and an abnormality is detected in an AI-based or rule-based manner. However, the safety of the subsequent operation is not determined at a point in time when the receive coil is mounted. That is, in the related art, an abnormal event or inconvenience that has occurred in the progression of a transportation operation can be detected, and measures can be taken against the abnormal event or inconvenience, but in a case in which measures are required, such as returning the subject to a pre-transport state and re-mounting the receive coil, for example, it requires time for the measures, which hinders operational efficiency. In addition, not only from the viewpoint of safety but also from the viewpoint of image quality, the optimal mounting of the receive coil and the use under an optimal condition are not taken into consideration.
An object of the present invention is to provide a technology for determining safety of a subject during a patient setup operation while ensuring image quality of imaging, and allowing an operator to avoid an operation in which safety cannot be ensured.
In order to achieve the above-described object, a receive coil mounting position on a subject before a receive coil is mounted is presented, and a camera image of the subject after the receive coil is mounted is acquired, the acquired camera image is used to determine safety, and a result thereof is presented.
That is, according to an aspect of the present invention, there is provided an imaging support device that supports an operation of setting up a subject in an imaging apparatus including an imaging space and a table on which the subject is placed and which transports the subject to the imaging space, the imaging support device comprising: a camera image acquisition unit that acquires a camera image of the subject placed on the table; an optimal disposition presentation unit that uses the camera image to present an optimal disposition of equipment to be mounted on the subject; and a determination unit that determines safety of the setup operation by using a camera image of the subject on which the equipment is mounted.
A determination result of the determination unit is presented to the operator or fed back to the optimal disposition presentation unit.
According to another aspect of the present invention, there is provided a magnetic resonance imaging apparatus having a function of the imaging support device described above as a function of a calculation unit.
In addition, according to still another aspect of the present invention, there is provided an imaging support method of supporting an operation of setting up a subject in an imaging apparatus including an imaging space and a table on which the subject is placed and which transports the subject to the imaging space, the imaging support method comprising: a camera image acquisition step of acquiring a camera image of the subject placed on the table; an optimal disposition presentation step of using the camera image to present an optimal disposition of equipment to be mounted on the subject; a determination step of determining safety of the setup operation by using a camera image of the subject on which the equipment is mounted; and a result presentation step of presenting a determination result of the determination step.
According to the aspects of the present invention, by disposing equipment, such as a receive coil or a cable connected to the receive coil, at an optimal position with respect to the subject, it is possible to transport and position the subject in a magnetic field space while ensuring image quality of imaging and securing safety. As a result, it is possible to execute the transportation operation without interruption and to improve the efficiency of the operation together with operation safety.
Hereinafter, embodiments of the imaging support device according to the present invention will be described. In the following description, a case will be described as an example in which an imaging apparatus is an MRI apparatus and equipment mounted on a subject is mainly a receive coil of the MRI apparatus, but the present invention can also be applied to an imaging apparatus that is an apparatus which includes an imaging space and which performs imaging by transporting the subject into the imaging space, for example, a CT apparatus or a PET apparatus, and may also be applied a case in which the equipment is a biological information measurement apparatus such as an oxygen concentration meter or a heart rate monitor.
First, an imaging apparatus that is a target of an imaging support device will be described.
The imaging apparatus 2 includes one or a plurality of cameras 3 installed at a position where the subject 6 before being transported into the imaging space can be imaged, and acquires a camera image of the subject 6 placed on the table 22 of the patient table device. The type, the number of installation, and the installation position of the camera are not particularly limited. In
Further, the camera 3 may be a camera that acquires a two-dimensional video or may be a stereo camera that enables the grasping of three-dimensional positions. Additionally, a camera having a video function or a tracking function, or the like may be used. Regardless of the type of the camera, an image acquired by the camera will hereinafter be referred to as a camera image. That is, in the present specification, the “camera image” is used in a broad sense to include not only an image acquired by a camera in a narrow sense but also an image acquired by an optical imaging apparatus.
Inside the gantry 21, in a case of the MRI apparatus, a static magnetic field magnet, a gradient magnetic field generation magnet, an RF transmission coil, and the like are disposed in this order, and a uniform static magnetic field generated by the static magnetic field magnet is generated in the imaging space. The RF transmission coil may also serve as an RF receive coil that receives a nuclear magnetic resonance signal generated by the subject, but an RF receive coil 7 is mounted on the subject in order to receive the nuclear magnetic resonance signal with high sensitivity.
As shown in
An MRI apparatus 2A further comprises a computer 20 that performs control of the entire apparatus and calculations such as image reconstruction using the nuclear magnetic resonance signal detected by the RF reception unit 214. An external storage device 4 that exchanges data, calculation results, or the like required for the control or calculation of images or a UI unit 5 provided with a device 50 such as a display device is connectable to the computer 20.
Since an imaging procedure by the MRI apparatus 2A is the same as that of a general MRI apparatus, the description thereof will be omitted in the present specification.
An imaging support device 1 is a device that supports a preparation process of placing the subject 6 on the table 22, mounting the receive coil 7 on the subject 6, and transporting the subject 6 to a predetermined position in the imaging space, in a case in which imaging is performed by using such an MRI apparatus 2A. The imaging support device 1 can be constructed in a general-purpose computer or a workstation and may be incorporated into the computer 20 of the MRI apparatus 2A. In addition, it is also possible to implement a part of functions of the imaging support device 1 by using a programmable IC or the like.
In addition, to the imaging support device 1, as accessory devices, the camera 3 that is installed in the imaging apparatus 2 at a position where the subject 6 can be imaged, an external storage device 40 that stores data and the like used for the determination of the determination unit 14, and the device 50 connected to the UI unit 15, such as a display device, an input device, and a sound generation device, are connected. In a case in which the imaging support device 1 is incorporated into the computer of the imaging apparatus, such as the MRI apparatus 2A, as shown in
Although the installation position or the like of the camera 3 has been described in the description of
The camera image acquisition unit 13 acquires the camera image from the camera 3 at a predetermined timing, and passes the camera image to the determination unit 14 and displays the camera image on the display device of the UI unit 15. The timing at which the camera image acquisition unit 13 acquires the camera image may be a timing at which the operator issues an instruction via the UI unit 15, or may be automatically acquired at a constant interval or at a predetermined timing programmed in advance.
The determination unit 14 analyzes the camera image of the subject 6 on which the receive coil 7 is mounted, and determines whether or not the safety in a case in which subject 6 with the receive coil 7 mounted thereon is transported into the bore is secured. The camera image of the subject before the receive coil is mounted is also acquired as necessary. States in which safety becomes a problem include: for example, as shown in
The optimal disposition presentation unit 11 determines the optimal position at which the receive coil should be mounted from the viewpoint of the image quality, for example, based on the camera image of the subject before the receive coil is mounted and examination information of the subject, and presents the optimal position on the camera image appearing on the display device of the UI unit 15. Details of a determination method of the position by the optimal disposition presentation unit 11 will be described below.
Next, the embodiment of processing of each unit will be described based on the configuration of the imaging support device 1 described above.
In the present embodiment, basic processing of the imaging support device 1 will be described with reference to the flow shown in
The camera image acquisition unit 13 acquires the camera image captured by the camera 3 in a state in which the subject 6 is placed on the table 22 of the patient table device (S1). The camera image deviates from the actual distance and position relationship in the subject depending on the position where the camera 3 is disposed, but it is also possible to calibrate the camera image by using information on a distance or an angle between the camera and the subject, or the like, and the image after the calibration may be used as the camera image.
The optimal disposition presentation unit 11 determines a position at which the receive coil 7 should be mounted on the subject 6, based on the examination information input via the imaging apparatus 2 or the UI unit 15, and displays the position on the camera image displayed on the display device of the UI unit 15 (S2).
A method of determining and presenting the optimal disposition of the receive coil from the viewpoint of the image quality is not limited, but for example, in a case in which a user designates an examination site, for example, a position of the heart, on the camera image displayed on the display device, a position where the center of the receive coil coincides with the center of that position is determined as the optimal disposition, and the optimal disposition is presented on the camera image. Alternatively, the examination site of the subject is irradiated with projection light from a projector provided in the imaging apparatus, and the position of the receive coil is presented on the camera image such that the center of the receive coil coincides with that position. In this case, receive coil information including the type, the size, and the shape of the receive coil may be stored in advance in the external storage device 4, and then the stored information may be read out for a receive coil used for actual imaging, and an appropriately scaled figure of a contour of the receive coil is disposed on the camera image, thereby displaying the position on the camera image. In addition, simply, a template image showing an optimal mounting site where the image quality is taken into consideration may be prepared in advance for each examination site, and then imaging information including the examination site may be acquired from the imaging apparatus 2, and the template image may be presented.
The camera image acquisition unit 13 acquires the camera image captured by the camera after the receive coil is mounted, from the camera image captured by the camera 3 in a continuous manner or at predetermined intervals, and passes the acquired camera image to the determination unit 14 (S3). A timing at which the camera image after the receive coil is mounted is acquired or passed to the determination unit 14 may be determined by the user via the input device or the like of the UI unit 15, or a timing at which the receive coil 7 is connected to the imaging apparatus 2 (receiver) may be received from the imaging apparatus 2 and may be used as the timing of the camera image acquisition.
The determination unit 14 analyzes the camera image in a state in which the receive coil is mounted on the subject and checks the safety. For example, as shown in
The protrusion from the table 22 can be determined, for example, based on a difference from an image of only the table acquired in advance as a reference image.
By determining the protrusion of the receive coil 7 or the accessory part thereof in this way, it is possible to prevent a remaining coil portion from being entangled in the structure of the imaging apparatus, such as the patient table device, because of the movement of the subject in a case in which the receive coil is wound around the limbs or the like.
For loop formation, in a case in which the loop occurs at a point in time when the receive coil is disposed, the loop detection unit 17 can determine the presence or absence of a loop-shaped figure by performing image processing on the camera image. For the loop that may potentially occur during the transport, the determination unit 14 predicts the occurrence of the loop as the table 22 moves, based on a traveling state of the cable 71 between the receive coil 7 and a receive coil connection portion 72. For example, in a case in which the cable 71 that is led out of the receive coil 7 is disposed along a body axis direction of the subject 6, and is gently bent in the vicinity of the connection portion 72 and connected to the connection portion 72, there is a lower possibility of a loop occurring between the subject 6 and the cable 71 even in a case in which the table 22 moves, but in a case in which the cable 71 is disposed to deviate from the subject 6, the loop is likely to be formed as the table 22 moves, and in some cases, there is also a possibility of protrusion from the table 22. That is, for a cable having a predetermined length from a cable connected portion of the receive coil 7, by detecting the length or the angle with respect to a table movement direction, it is possible to predict the likelihood of loop occurrence. The determination unit 14 detects a distance between the cable connected portion and a table end part, the length of the cable, an angle of the cable traveling, and the like from the camera image, predicts the loop occurrence based on the result, and checks the safety.
By detecting geometric information of the cable during the disposition of the receive coil in this way and predicting the subsequent change, it is possible to preemptively perform detection and issue a warning against the loop occurrence and risks such as the cable being wound around a part of the subject, for example, an arm.
Whether or not the clearance is sufficiently maintained is determined by comparing the result of actually measuring or estimating the size (body thickness or abdominal girth) of the subject or the subject after the equipment or the like is mounted with the size of the bore, which will be described in detail in Embodiment 2.
It is preferable that the determination unit 14 checks the safety by detecting a cable of an SPO2 sensor attached to a finger of the patient or a blanket placed on the patient, in addition to the safety check regarding the patient position, the coil position, and the cable (Case 1 to Case 3). In particular, a thin blanket or the like may be entangled in the table and a support portion thereof during table movement. For the concern of such entanglement, the determination unit 14 can predict the occurrence of entanglement by detecting the blanket and determining the placement status of the blanket, for example, whether or not the blanket position is within a predetermined range, whereby it is possible to prevent the entanglement.
In addition, the above-described prediction is to determine conditions that inhibit the safety in a rule-based manner, but it is also possible to perform the prediction using a machine learning model or AI that has learned various pieces of image data that inhibit the safety. That is, a part or all of the determination unit 14 can also be constructed by using a machine learning model or AI.
In a case in which it is determined that there is a problem in the safety as a result of the determination (in a case of NG determination in S4), the determination unit 14 issues an alert via the UI unit 15 (S5). The alert may be displayed on, for example, a gantry monitor installed at an entrance of the bore as OK or NG from the viewpoint of safety, or a notification may be issued with an alert sound. Further, as the alert display, for example, a problematic area may be indicated by being surrounded by an arrow or a square on the camera image displayed on the display device. Alternatively, an icon, a template image, or the like may be displayed. As a result, the user can immediately recognize the problematic area and can take measures against the problematic area.
After the user takes measures against the area where there is a problem in the safety in response to the alert, the camera image acquisition unit 13 acquires the camera image again (S6). For example, in a case in which there is a problem with the position of the receive coil, the user takes measures such as re-disposing the receive coil while maintaining the initially presented optimal disposition as much as possible.
The camera image acquisition unit 13 passes the camera image after measures are taken against the problematic area (for example, after the receive coil is re-disposed) to the determination unit 14 and repeats the processing S4 to S6 until it is checked that there is no problem in safety.
After that, the table 22 is moved to transport the subject 6 into the imaging space such that the center of the receive coil 7 is located at the center of the bore, that is, the center of the static magnetic field space. Although not shown in
As described above, according to the present embodiment, by transporting the subject 6 into the imaging space by ensuring safety in a state in which the receive coil 7 is mounted at the optimal disposition in which the image quality is taken into consideration, it is possible to secure the safety in the setup operation while ensuring the image quality, and it is possible to eliminate the need to repeatedly move the table, and to prevent the inappropriate disposition caused by re-mounting of the receive coil, image quality degradation due to the inappropriate disposition, and the like.
In the present embodiment, an imaging support device provided with a function of determining whether a sufficient clearance is secured between the subject 6 covered with the receive coil 7, the blanket, or the like and the imaging space (the inner wall surface of the bore) will be described particularly as a safety check matter.
The imaging support device 1 of the present embodiment comprises the body thickness estimation unit 16 in order to perform the determination, and the body thickness estimation unit 16 estimates the body thickness (a thickness in a direction perpendicular to a table surface) of the subject 6 from the camera image. A functional block diagram of the device of the embodiment is the same as that of
First, the optimal disposition presentation unit 11 presents the optimal disposition of the receive coil by using the camera image (S1, S2), and the camera image acquisition unit 13 acquires the camera image after the receive coil is mounted (S3). The body thickness estimation unit 16 estimates the body thickness by using the camera image (S31).
In a case in which the camera 3 is provided beside the patient table, a side surface of the subject appears in the camera image, so that the height of the subject in the perpendicular direction, that is, the body thickness of the subject, can be estimated from the image. Alternatively, in a case in which the camera 3 is a stereo camera, the body thickness of the subject can be estimated from two camera images captured in directions with different angles.
The determination unit 14 determines the sum of the body thickness estimated by the body thickness estimation unit 16 and the thickness of the receive coil 7 acquired in advance as the thickness of the examination target, calculates a difference between a geometric numerical value (the elliptical shape, the height, and the width) of the imaging space and the thickness, and determines whether the difference is within an allowable clearance (S4). An appropriate range of the clearance is determined in advance for each apparatus in consideration of the intensity of the magnetic field generated by the RF transmission coil stored in the gantry, and for example, the determination unit 14 acquires the clearance from the external storage device 4 or the imaging apparatus 2.
The determination unit 14 issues the alert in a case in which it is determined that the distance between the examination target and the inner wall surface of the bore does not satisfy a predetermined clearance based on the result estimated by the body thickness estimation unit 16 (S5), which is the same as in the flow of
In a case in which the user re-disposes the receive coil after the alert is issued, the camera image is acquired (S6), and steps S4 to S6 are repeated.
In that case, as indicated by dotted lines in the flow of
As a result, the receive coil can be mounted on the user while securing the safety and ensuring the image quality.
Although a case has been described in
According to the present embodiment, it is possible to determine whether a patient having a large physique (large abdominal circumference) can fit into the bore in a case in which the patient is to be placed inside the bore. Further, it is possible to preemptively determine a safety inhibiting condition after the disposition of the equipment or the like, which is difficult to determine at a glance, and then it is possible to find the optimal disposition of the receive coil. As a result, it is possible to prevent the discomfort of the subject due to the insufficient clearance or, in extreme cases, the influence on the subject caused by extremely close distance to the RF transmission coil.
In Embodiments 1 and 2, a case has been described in which the processes from the determination step S4 to the camera image acquisition step S6 after the receive coil is re-disposed are repeated until the determination unit 14 determines that there is no problem in safety, but the present embodiment provides a method for efficiently performing the setup by limiting the number of repetitions to an appropriate range.
Therefore, in the imaging support device 1 of the present embodiment, the determination unit 14 counts the number of repetitions, and the optimal disposition presentation unit 11 presents an option of the disposition of the receive coil different from the initially presented disposition of the receive coil. Since the configuration of the device is the same as that of the other embodiments, the processing of the imaging support device 1 of the present embodiment will be described with reference to the flow of
After the camera image is acquired (S1), the optimal disposition presentation unit 11 presents the optimal disposition of the receive coil by using the camera image (S21). This step S21 is basically the same as step S2 of Embodiments 1 and 2, but here, a mounting position is presented after excluding a setup position where there is a problem from the viewpoint of safety. For example, in a case in which the examination site is shifted from the center of the subject in a left-right direction, such as the heart or one of the arms or legs, or in a case where the examination site is spread out, setting up the receive coil such that the center of the receive coil is located at the center of the examination site may potentially cause the receive coil to protrude from the table end part with a multi-channel coil having a relatively wide area. The optimal disposition presentation unit 11, for example, compares the position or the range of the examination site specified in the camera image with the size of the receive coil and presents the optimal position of the receive coil by excluding the setup position where the receive coil protrudes from the table.
The exclusion of the safety NG in this step may be simpler than the safety determination by the determination unit 14, but by excluding the disposition with the safety problem that can be easily predicted in advance, the number of repetitions of the subsequent safety determination loop can be reduced.
After the receive coil is mounted on the user in accordance with the presented position of the receive coil, the determination unit 14 acquires the camera image after the mounting (S3) and determines whether or not the safety is maintained (S4). In a case in which the safety is NG, the alert display (S5) and the acquisition of the camera image after the receive coil is re-disposed (S6) are performed, and the safety is determined again (S4). However, the determination unit 14 monitors the number of times the safety determination is repeated, that is, the number of times the re-disposition is repeated (S7), stops the determination loop in a case in which the number of times is equal to or greater than a predetermined number of times (N), and causes the optimal disposition presentation unit 11 to present a second option (S71). The second option is a disposition in which equivalent image quality to the initially presented optimal disposition of the receive coil or relatively higher image quality in terms of the image quality can be ensured, and includes the use of the receive coils with different types and the dispositions thereof.
For example, in a case in which the alert persists even after repeated re-dispositions for a patient with a large body type because the initially presented disposition may be optimal from the viewpoint of the image quality but the patient can be barely disposed due to the distance between the patient and the bore, as shown in
In a case in which the receive coil is disposed in the presented second optimal disposition, the camera image acquisition unit 13 acquires the camera image (S72), and steps S4 to S7 described above are repeated again.
According to the present embodiment, there is no need to repeatedly perform one optimal disposition operation proposed in terms of the image quality, thereby allowing for efficient operation. Although not shown in
The present embodiment is an embodiment in which, in a case in which the receive coil is the multi-channel coil, a function of presenting the optimal coil position for improving the image quality, in addition to the mounting position of the receive coil, is added to the optimal disposition presentation unit 11.
A receive coil that is currently widely used in the MRI apparatus is a multi-channel coil in which a large number of surface coils are disposed in order to enhance sensitivity and enable wide-range imaging. The multi-channel coil has an advantage that a relatively wide region can be imaged at high sensitivity at once, but in a case of imaging a limited examination site, there is also a possibility that noise may be increased because a signal from a coil of a channel located at a position relatively far from the site is also included in the image reconstruction. In addition, in the multi-channel coil, there is also a coil having a large number of channels as compared with receiver channels of the receive coil of the imaging apparatus 2, and in this case, it is necessary to select which channel to use or not to use.
In the imaging support device 1 of the present embodiment, in a case in which the multi-channel coil is used, a function of presenting one or a plurality of optimal channels in terms of the image quality among the large number of channels constituting the multi-channel coil is added. The channel presentation function may be a function of the optimal disposition presentation unit 11 shown in
In step S20, first, the optimal disposition presentation unit 11 presents the optimal position of the receive coil from the viewpoint of the image quality. In that case, the optimal disposition is presented after excluding the setup position with a problem from the viewpoint of safety. This processing is the same as that in step S21 of
In that respect, the channel presentation unit selects channels within a predetermined region including the examination site among the plurality of channels of the receive coil as active channels.
Information indicating the optimal channel is reflected in the imaging apparatus 2. As the reflection method, for example, the user may perform a setting of manually activating the channel by using the presented information on the optimal channel, or the information indicating the optimal channel is sent to the imaging apparatus 2 together with the geometry information of the multi-channel coil and the optimal channel automatically selected on an imaging apparatus 2 side may be turned ON.
As described above, presenting the optimal position of the receive coil and the optimal channel in step S20 and then acquiring the camera image after the mounting, predicting the safety, and issuing the alert as necessary (S4 to S6) are the same as those in other embodiments, and the description thereof will be omitted. In the present embodiment as well, as in the flow of
According to the present embodiment, it is possible to ensure high image quality and support safe setup by presenting the optimal channel in addition to the optimal mounting position.
Although embodiments have been described above in which the imaging support device and the imaging support method of the embodiment of the present invention are mainly applied to the MRI, the present invention can be applied not only to the MRI apparatus but also to an apparatus that transports the subject into a bore and that performs imaging. In addition, the individual embodiments or the individual processing included in the individual embodiments can also be appropriately combined as long as there is no technical contradiction, and such a combination is also included in the present invention.
| Number | Date | Country | Kind |
|---|---|---|---|
| 2023-158720 | Sep 2023 | JP | national |
